Uranium Deposits

Abstract

North Choibalsan ore district, including the Dornod deposit in East Mongolia, is the largest uranium district in Mongolia and comprises volcanic-related U-Mo-F deposits of Late Jurassic-Early Cretaceous age, in bimodal volcanics of the Mongol-Priargun belt. In southern Mongolian, most of the known uranium deposits are related to Late Mesozoic sedimentary basins in permeable terrigenous sandstone aquifers. These are classified as sandstone uranium deposits, and the source of uranium may be Upper Paleozoic granites and older basement. In addition, young surficial uranium mineralization was recently discovered in Quaternary alluvial sediments. Also, uranium, petroleum, and coal deposits are hosted in the Late Mesozoic-Cenozoic sedimentary basins. Based on an airborne gamma-ray spectrometry survey in southwest Mongolia, the uranium ore districts (Khovd, Gobi Tengeruul) and ore clusters (Khustain Nuruu, Songint) have recently been discovered. Other types of uranium mineralization in Mongolia include uranium in Lower Cretaceous lignite seams, in Mesozoic alkaline intrusions with related REE and Th-U, and in metasomatic rocks, migmatites, and pegmatites localized in Precambrian metamorphic rocks. Mineral Resources and Petroleum Authority of Mongolia reports that uranium resources in Mongolia are assessed at a total of 166,657 tonnes in 2019.